--- ghc/compiler/Makefile.sav	2006-05-26 12:44:17.000000000 -0400
+++ ghc/compiler/Makefile	2006-05-26 12:44:58.000000000 -0400
@@ -395,7 +395,8 @@
 SRC_HC_OPTS += -DGHCI -package template-haskell
 
 # Use threaded RTS with GHCi, so threads don't get blocked at the prompt.
-SRC_HC_OPTS += -threaded
+# Disable threading for 6.4.2 on darwin (causes RTS crashes):
+# SRC_HC_OPTS += -threaded
 
 ALL_DIRS += ghci
 
